1. Field of invention
The present invention relates to an electronic still camera, and more particularly, is applicable to the case where an image signal is recorded in large-capacity recording medium, such as an optical disc, etc.
2. Description of the related art
Heretofore, electronic still camera imaged a desired object through a solid-state imaging device, and recorded the image signal in a recording medium.
A large amount of image information can be recorded when a magneto-optical disc, etc. is used as a recording medium.
Moreover, if flash memory (FE.sub.2 PROM) comprising an IC card is used as a recording medium, a large amount of image information can be recorded. Additionally, flash memory does not need any backup power supply, so that the IC card can be easily changed, if necessary.
An image formed of such image data is typically of one to several megabytes. In comparison, 113 megabytes of data can be recorded in a mini disc, which is a magneto-optical disc having diameter of 2.5 inches and capable of recording and reproducing an audio signal, and 20 megabytes of data can be recorded in an IC card flash memory.
However, these types of recording medium require a long recording time and, hence continuously taking pictures. Continuous shooting becomes difficult when these types of recording medium are used.
More specifically, this type of magneto-optical disc needs about 6.8 seconds to record 1 megabyte of data, and flash memory needs about 1.5 seconds to record 1 megabyte of data.
As a means of solving this problem, SRAMs composed of IC card or hard disc drive may be used.
A SRAM only needs a short recording time. More specifically, 1 megabyte of data can be recorded in about 0.25 of a second.
However, since a SRAM needs a backup power supply, a problem occurs in that it becomes difficult to make a SRAM using removable IC cards.
Also, since only 8 megabytes of data can be recorded in a SRAM, another problem arises that the recording capacity of SRAM is less than the data capacity of the magneto-optical disc or flash memory.
Also, the hard disc is inferior in reliability to the magneto-optical disc and flash memory.